I removed the lower panel that appears to conceal the instrument panel J/B yesterday, and took a picture of what looks like it might be the back of it (attached), but obviously I'm not sure. Unfortunately I don't have a schematic that shows the layout of this J/B which might help to identify it. You can see the "J 4" label on it but I don't recall seeing that in any of the schematics I've had access to. Looks like it could be a challenge to get at.

Joe, it would be helpful if you could find a drawing like the one I have attached for the RAV4 4.3 models. In Canada our Canadain Tire stores provide free customer access to the Mitchell On Demand computer system. Perhaps you can find something similar were you live.

You may also be able to identify the proper connector by looking for the one with 2 blue/yellow wires adjacent to one another (L6 & L7). At that point you may be able to just wiggle the connector to clean off any corrosion, or better yet, pop the locking tabs and pull the connector away from the junction box.

If you have a real problem with access, then spraying with contact cleaner would be a good last attempt. Also a reminder that if you want to try the hack job, you could also make a 12v connection inside the dome light housings if you can fish a 12v source to that area. Perhaps you already have a power source in that area for a Moon Roof or a powered mirror.If you do this make certain you remove the existing blue/yellow wires from the lamps in case the corrosion clears itself later and you end up feeding 12v back down to the junction box.

Thanks Rickl,
I'm not aware of on demand schematics available where I live in Westchester NY, but after studying my own cell photos and the schematics I was able to obtain, I feel like there's a chance I might be able to detach the Instrument Panel J/B from its mounting, and assuming the wiring isn't taut I can access the L6/L7 wires. When I get the chance to do so, I'll report my results whether I have any luck or not.

I feel like there's a chance I might be able to detach the Instrument Panel J/B from its mounting, and assuming the wiring isn't taut I can access the L6/L7 wires.

You don't really need to remove the whole junction box from it's mounting, you only need to unplug the proper connector from the J/B. This probably won't require an tools other than a screwdriver to pop the locking tab. The awkward position is going to be the biggest problem. I expect that just getting the connector to move 1/4" may be enough to disturb any corrosion.

Remember to disconnect your battery when working around the JB to avoid accidental shorts which will make your problems even worse

Yes, I'd figured the inconvenience of disconnecting the battery is well worth protecting against a new problem.

The 'front' part of the JB where the connectors are plugged in is facing away, into the firewall. I had only examined it briefly with the lower panel off, but I think the space was too tight to see anything above the bottom of it. I hadn't really tried yet but it didn't seem like I could even squeeze my cell phone in front of it to take a photo. But obviously I'd like to take the path of least resistance so if there's a way to locate and access the right connector without unmounting the whole J/B (which itself could be difficult) I'll try that first.

Had the chance yesterday to try getting at the instrument panel J/B. It was easy to remove the panel below the dashboard, and the metal plate behind that. After that, there was a metal bracket that one of the J/B bolts secures to. That one wasn't as easy because I didn't have the proper socket extension, but I managed ok. My hope was that I'd be able to pull the J/B down below the dashboard, or flip it around to access the connectors on the back side. I tried, carefully, to do so but in the end there just wasn't enough slack in the wiring without disconnecting at least one of the harnesses. I didn't have the stomach to try that because until we buy another car in two months, any mistake I make could leave us completely stranded.

The best I was able to do in this attempt was to snap a couple of photos (attached). One is of the front (or back?) of the J/B with the lower panel removed. The other was the best shot I could get reaching around behind it with my cell phone. Sadly, there was no 'aha' moment. I don't have the schematic for the connectors, and so can't determine which is the one of interest. I tried to identifying it by correlating the grouping of wire colors to the wiring diagrams I do have, but wasn't able to draw any conclusion from that. Finally, even if I could identify the correct one I don't know how I'd access it without being able to flip the J/B around; doing it blindly with one hand doesn't sound like an option.

At this point as much as I don't prefer it I'm willing to implement the hack solution, but it's not clear to me where the best place is to splice in to a 12V source. Any advice for finding a lead that is always hot (as interior lights require), and is protected by one of the 15A fuses?

I attached a photo of the 5 wires running up the left windshield column with the panel removed- 2 BLU/YEL, 2 RED/YEL, 1 WHT. Is it a good assumption that the BLU/YELs are the 12V leads to the personal and dome lights?

Two Blue yellow wires ( one to the interior light, and one to the personal light)

One Red/wht wire going down to the dashboard warning light

One Red/yel wire going to the door switches

One white/blk wire going to ground

These colors seem to match up with your photo with the exception that we can't see any black markings on the white wire (perhaps there is a black stripe that we can't see on the photo) . Also according to the schematic the white/Blk wire attaches to ground near the left side of the roof, and may not run down the A-pillar at all.

Based on this information I believe that the 2 blue/yellow wires that you see, are the wires in question. You can prove this without cutting any wires by using a pin to pierce the insulation, and then measure the resistance from the wire in the pillar to the blue/yellow wire in either of the two lamp housings.

After proving that these are the correct blue/yellow wires, I suggest you look for a convenient place to cut the two wires. This could be below the dash, or in the pillar. You will then connect the two wires coming from the roof to a new wire which in turn will connect to a fuse which is hot all the time. You can do this using fuse taps to avoid the need to cut and splice any additional wires.

You could temporarily touch this new wire to a 12V source like the cigar lighter to prove it will work before spending any time or money to purchase the fuse taps.

I would still suggest trying to wiggle the connectors on the junction box which may clean any corrosion causing the bad connection.

Thanks Rickl, when I get the chance I'll try reaching around again to wriggle the connectors I can physically touch, as a long shot since I can't unlock them without better access to the J/B at this time. I wasn't aware of fuse taps, and feel a lot better about the hack idea doing that instead of splicing into a lead somewhere. I have less trepidation about splicing the leads in the windshield column.

When I next have the chance (hopefully this weekend) I'll first confirm the personal lights test you described, then go ahead with the hack.

That's awfully tempting DD, the Doc must be very popular if lunch at Wendy's is his fee

It seems like I still have a bit of a challenge re: the hack, albeit hopefully a smaller one. The fuse panel under the dash board (also the one in one of the photos I recently posted) only has one 15A fuse, CIG/RADIO. That one isn't always hot as the personal lights require for normal functioning. If I'm going to try a hack solution, I at least want to get them working as designed.

The actual DOME fuse is in the box to the right of the engine. I'm wondering if it's possible to tap to that one and wire through the firewall. I haven't taken a close look at that area yet, and so have no idea at the moment whether that could be done or would be difficult / impossible. If it is, any other thoughts on getting a 12V lead to BLU/YEL?